partially worn tires on AWD

jcarr112 · Post by **jcarr112** » 13 Apr 2010, 13:49

I have an S60 AWD 2006, the tires have about 12000 miles, had a flat yesterday and the dealer is tellingme i need to change all 4 or I'll ruin the AWD? makes sense to change 2, but not 4, tires are hardly worn and I would expect the suspension to compensate for the thousands of an inch wear? Or am I off the wall on my assumption and instead of replacing 2 tires, I have to replace all 4.

Post by **MadeInJapan** » 13 Apr 2010, 16:04

Thousands of inches difference (I think the tolerance is 3/1000's but others might chime in), you should be okay- just do the one axle and you should be good. Besides, the newer AWD systems are more rugged. If it was one of Volvo's first AWD systems, I might agree with the dealer, but on an '06- Nah...

Post by **JDS60R** » 13 Apr 2010, 17:18

Don't worry. The 2001 and newer AWD Volvo's can compensate not only for a new tire while the others are slightly worn but for a spare tire which is vastly different in size. This was a complaint by many Volvo owners pre-2001 and the new system was designed to handle a much larger difference in wheel diameters. The vehicle understands the difference in diameter by using the ABS sensors while the car is traveling straight forward to measure the tire diameters.

The system can distinguish diameter but it can not distinguish tire grip until the brakes are applied and then the ABS and TRACS unit compensate. ABS and tracs do not know if the level of grip is provided by the tire or the brake pads.

Either way - 1 new tire and you are fine.
See the "puncture" section in this 2001 brochure